Compositions based on olefin polymers, such as polyethylene, have been suggested for use as insulation about electrical conductors. As a general rule, these compositions have been modified by the addition thereto of additives designed to improve the flame retardant properties of the compositions. For example, inorganic fillers exemplified by polar compounds such as aluminum trihydrate, non-calcined clay and the like have been added to compositions, based on olefin polymers, for the express purpose of improving flame retardant properties.
Although the addition of polar compounds to olefin polymer compositions does improve the flame retardant properties thereof, such addition gives rise to other problems. For example, olefin polymer compositions containing polar compounds are adversely affected by moisture. Consequently, when these compositions are extruded as insulation about electrical conductors and the insulated conductors subjected to a wet environment, the insulated conductors have been found to have unstable wet electrical properties. Unstable wet electrical properties are manifested by decreased insulation resistance.